Auckland
November
Q.
Hi Tui, my Luisa plum tree has tiny hold in the leaves. I have used a Rose Bug spray, it didn't stop whatever is making the holes. I asked a chap who has over 30 plum trees, he said use dish washing liquid, but that hasn't worked either. I noticed there are ants on the branches. Please help as I do not want anything to happen to my tree. Many thanks Peggy
Peggy
A.
Hi Peggy, it sounds like your tree has what is called Shot Hole, this is a common fungal disease of stone fruit and looks like holes in the leaves from a shot gun. It is common in spring especially if it has been a wet winter, followed by a wet spring. The fungal spores overwinter in the leaf nodes and infected buds on the tree, so it is important that in autumn all infected leaves, buds and twigs are removed and burnt rather than composted, and also regular sprays with a copper based fungicide in winter (commonly called a clean-up spray). Shot Hole is difficult to control using fungicide sprays, it is spread by rain splash, so prevention is better than cure and cultural practices are best, picking up fallen infected leaves from around the tree and disposing of the plant material by burning or in the rubbish. And applying a copper based spray in winter will also help. Rose Bug spray is an insecticide and should control whatever the ants are attracted to which will be the honey dew excreted by common sucking insect such as scale, aphids or mealy bug. Insects such as small bronze beetles can also cause this sort of damage, they only hang around for a few days and move on, so I think you probably have Shot Hole. Make sure your tree is regularly fed with a balanced fruit tree fertiliser such as Tui Citrus Food in spring and again in autumn. Water during the growing season and mulch around the tree to help conserve soil moisture and keep weeds at bay.
Post a comment
What is wrong with my Luisa plum tree, it has got holes in the leaves? Comments
Last season my Luisa plum started losing the tips of the leaves after a huge number of flowers in Spring some fruit was formed. Eventually all the leaves were gone and the fruit never formed. On advice I sprayed several times with Neem oil and eventually the tree recovered, but never bore any fruit. Over the summer the tree completely recovered and is very healthy looking and covered in leaves. How can I stop the same thing happening this Spring? Oamaru North.
Cliff Butson
Hi Cliff, it sounds like your tree could have been hit with a fungal disease such as brown rot, or similar. Now is a good time to do clean up sprays on your fruit trees, spray with copper oxychloride and spraying oil in autumn to capture any overwintering fungal spores and insect eggs, and then again in winter when the tree is dormant. You can spray right up to just before flower bud burst, stop spraying with copper and oil until fruit has set, then give the tree another spray. Make sure you collect up the fallen leaves and any mummified fruit on the ground to prevent disease spreading. The other thing it could have been is a late frost, which would have knocked back the soft new growing tips, flowers and developing fruit. Luisa plums are frost tolerant once established, a late frost can affect fruit set and cause plants to defoliate.
Lianne